Ambjørnsen, E., Valderhaug, J., Norheim, P. W. Fløystrand, F. Assessment of an additive index for plaque on complete maxillary dentures.Acta Odontol. Scand. 1982, 40, 203–208There appears to be a relation between accumulation of plaque on complete maxillary dentures and denture stomatitis. the present index was introduced to assess the location and amount of plaque in some areas on the fitting surfaces of complete maxillary dentures. Scores were recorded in five defined areas on the denture base. Four ranked scores were used: 0-no visible plaque, 1 -plaque visible only by scraping on the denture base with a blunt instrument, 2 -moderate accumulation of visible plaque, and 3 -abundance of plaque. By summing up the scores from the five areas, the plaque was recorded on a scale from 0 to 15 points. the inter-and intra-reliability were tested for two examiners using the index on 50 complete maxillary dentures. Expressed in terms of Scott's Pi, inter-examiners agreement was 0.83, and intra-examiner 0.83 and 0.82 for examiners A and B, respectively. A simplification of the index was also presented. In this index the scores 0 and 1 were combined to score 0,—no visible plaque, and score 2 and 3 were combined to score 1, -visible plaque. Using this index, Scott's Pi was calculated to 0.91 for inter-examiner reliability. for the intra-examiner reliability Scott's Pi was calculated to 0.91 for examiner A and 0.89 for examiner B.